hal: add bus stream for front passenger zone

Add bus stream for front passenger zone playback
on automotive platform.

Primary zone         -> Mercury
Front passenger zone -> A2B1 (8CH DAC1) (ALL)
Rear seat zone       -> A2B2 (16CH DAC1&2) (SA81x5)
                        A2B1 (8CH DAC2) (SA6155)

Change-Id: Ib288f84c94d33f2f49d45b32d6810e0b91db967f
diff --git a/hal/audio_extn/utils.c b/hal/audio_extn/utils.c
index bb33885..a888a07 100644
--- a/hal/audio_extn/utils.c
+++ b/hal/audio_extn/utils.c
@@ -155,6 +155,7 @@
     STRING_TO_ENUM(AUDIO_OUTPUT_FLAG_SYS_NOTIFICATION),
     STRING_TO_ENUM(AUDIO_OUTPUT_FLAG_NAV_GUIDANCE),
     STRING_TO_ENUM(AUDIO_OUTPUT_FLAG_PHONE),
+    STRING_TO_ENUM(AUDIO_OUTPUT_FLAG_FRONT_PASSENGER),
     STRING_TO_ENUM(AUDIO_OUTPUT_FLAG_REAR_SEAT),
     STRING_TO_ENUM(AUDIO_INPUT_FLAG_NONE),
     STRING_TO_ENUM(AUDIO_INPUT_FLAG_FAST),